This invention relates generally to methods and materials for sealing a compartment and, more particularly, a method of thermally insulating a wall surface of a refrigerated container.
A refrigerated container is a portable enclosure having a self-contained refrigeration unit connected thereto and having a space within the enclosure for the storage of refrigerated goods. The goods may be frozen, in which case the container must be kept at below freezing temperatures, or it may be simply refrigerated goods, in which case the container must still be maintained at a relatively low temperature as compared to the surrounding ambient temperatures. In either case, in order to maintain the lower temperatures within the enclosure, it is desirable to insulate the container.
Where the container walls are planar in form, which is the case for most walls, it is relatively simple to provide a planar shape of insulating material over the entire planar surface of the wall. However, when it is non-planar form such as at the forward end wherein various components of the refrigeration system are disposed, it is difficult to use the planar sheets of insulation since they can not be easily bent around the non-planar surface, nor can they be easily made to adhere to those planar surfaces.
The common approach for insulating the non-planar portions of a refrigerated container is to install a spaced wall so as to thereby define an envelope or pod adjacent the non-planar wall. The envelope is then filled with liquid urethane foam which, when dried, provides sufficient insulation to that portion of the container.
There are various problems connected with the use of urethane foam in this manner. One problem is that the liquid urethane contains volatile organic contaminants (VOC's) that have a tendency to escape to the atmosphere and which are harmful thereto. With increasingly stricter regulations relating to this matter, greater efforts are being made to eliminate the use of liquid urethanes in the manufacturing processes.
Another problem with the prior art approach is that, prior to the insulation of the liquid urethane, it is necessary to seal all of the various openings in the envelope in order to prevent the liquid urethane from flowing outside the container. Generally this is accomplished by using a sealant such as caulk, to seal the various seams within the envelope. This practice is effective but very labor intensive. Also, the cost of materials for this practice can be relatively high.
It is therefore an object of the present invention to provide an improved method and apparatus for insulating a refrigerated container.
Another object of the present invention is the provision in a refrigerated container for effectively and easily insulating a non-planar portion of a wall thereof.
Yet another object of the present invention is the provision for insulating a refrigerated container without the use of undesirable and expensive materials.
Still another object of the present invention is a process for insulating a refrigerated container in an effective and an efficient manner.
These objects and features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.